Field of the Invention
This disclosure relates to the field of drilling, completing, servicing, and treating a subterranean well such as a hydrocarbon recovery well. In particular, the present disclosure relates to systems and methods for detecting and/or monitoring the position and/or condition of a wellbore, the surrounding formation, and/or wellbore compositions, for example wellbore sealants such as cement, using MEMS-based data sensors. Still more particularly, the present disclosure describes systems and methods of monitoring the integrity and performance of the wellbore, the surrounding formation and/or the wellbore compositions from drilling/completion through the life of the well using MEMS-based data sensors.
Background of the Invention
Natural resources such as gas, oil, and water residing in a subterranean formation or zone are usually recovered by drilling a wellbore into the subterranean formation while circulating a drilling fluid in the wellbore. After terminating the circulation of the drilling fluid, a string of pipe (e.g., casing) is run in the wellbore. The drilling fluid is then usually circulated downward through the interior of the pipe and upward through the annulus, which is located between the exterior of the pipe and the walls of the wellbore. Next, primary cementing is typically performed whereby a cement slurry is placed in the annulus and permitted to set into a hard mass (i.e., sheath) to thereby attach the string of pipe to the walls of the wellbore and seal the annulus. Subsequent secondary cementing operations may also be performed. One example of a secondary cementing operation is squeeze cementing whereby a cement slurry is employed to plug and seal off undesirable flow passages in the cement sheath and/or the casing. Non-cementitious sealants are also utilized in preparing a wellbore. For example, polymer, resin, or latex-based sealants may be desirable for placement behind casing.
To enhance the life of the well and minimize costs, sealant slurries are chosen based on calculated stresses and characteristics of the formation to be serviced. Suitable sealants are selected based on the conditions that are expected to be encountered during the sealant service life. Once a sealant is chosen, it is desirable to monitor and/or evaluate the health of the sealant so that timely maintenance can be performed and the service life maximized. The integrity of sealant can be adversely affected by conditions in the well. For example, cracks in cement may allow water influx while acid conditions may degrade cement. The initial strength and the service life of cement can be significantly affected by the water content and the slurry formulation. Water content, slurry formulation and temperature are the primary drivers for the hydration of cement slurries. Thus, it is desirable to measure one or more sealant parameters (e.g., moisture content, temperature, pH and ion concentration) in order to monitor sealant integrity.
Active, embeddable sensors can involve drawbacks that make them undesirable for use in a wellbore environment. For example, low-powered (e.g., nanowatt) electronic moisture sensors are available, but have inherent limitations when embedded within cement. The highly alkali environment can damage their electronics, and they are sensitive to electromagnetic noise. Additionally, power must be provided from an internal battery to activate the sensor and transmit data, which increases sensor size and decreases useful life of the sensor. Accordingly, an ongoing need exists for improved methods of monitoring wellbore sealant condition from placement through the service lifetime of the sealant.
Likewise, in performing wellbore servicing operations, an ongoing need exists for improvements related to monitoring and/or detecting a condition and/or location of a wellbore, formation, wellbore servicing tool, wellbore servicing fluid, or combinations thereof. Such needs may be meet by the novel and inventive systems and methods for use of MEMS sensors down hole in accordance with the various embodiments described herein.